1. Field of the Invention
The invention relates to a device for fixing stock rails in railway switches. The invention also relates to a process for fixing stock rails by means of such a device.
2. Description of the Prior Art
A device of the above mentioned type is taught in, for example, AT-PS 321 345. By means of such a device, there was achieved the advantage that a plate-shaped spring element could be introduced under substantially no tension and was brought into the desired tensioned position, in which the rail foot was resiliently held in position, only by running the cotter or cross-wedge into position. No special tools were necessary for assembly and the spring leaf could simply be put into the desired position, whereupon the desired tension was adjusted by the wedge.
DE-OS 32 30 612, teaches a device for fixing stock rails or track rails in railway switches, in which a spring element having a round shape, was under tension in a tunnel-shaped recess of a sliding chair for the purpose of obtaining in this manner a resilient fixation of a rail foot. In such known constructions it had been found that in cases of excessive stress there exists the risk that the spring element may become fractured. In particular, it has been found that a substantially lower spring force and thus a lower load of the spring element can be considered as sufficient in normal operation, whereas a progressive spring characteristic would be desirable in cases of a heavy load. An attempt to realize such a progressive spring characteristic is made in DE-OS 32 30 612, and for this purpose there is provided in the tunnel-shaped recess beside a first hump-shaped elevation, over which the spring element is run so as to put the spring element under pretension, a second hump-shaped elevation and the rail root. Such an arrangement results in a sliding chair of relatively complicated design. On account of using in this arrangement spring elements formed of bent round steel, the spring characteristic becomes extremely steep after having engaged the second hump-shaped elevation, so that a definite progressive spring characteristic can not be obtained easily. Furthermore, machining of the sliding chair and the design of the tunnel-shaped recess of the sliding chair are relatively expensive in this construction.